Marine Weather and Tide Forecast for White Pigeon, MI

DISCUSSION
Issued at 218 PM EDT Mon May 12 2025

An upper low pressure system is able to shift northward in a weakness in the flow as a trough enters the Western US. As it does so, its outer edges of energy pushes into the area and moisture will be advected into the area as well. As such, expect surface dew points to increase from the 40s this morning to the 60s by 00z this evening. This is maybe a little on the early side for these dew points to come in when compared to normal for Fort Wayne's obs, but it's not unheard of and it makes sense with a strong low level jet cranking moisture into the area with connection to the western Atlantic. Closer to home, the issue with getting precipitation is that there's so much dry air after our stretch of dry weather starting later last week. East winds closer to the surface is more of drying wind and RAP time sections show the depth of the dry air at least through midday at FWA and we'll likely have to wait until mid afternoon at the earliest to receive any rain. Despite the NAM showing 500 to 1000 J/kg of instability around, the ECMWF is much more reserved with only 500 J/kg at 18z and then waning after that.
Similarly the HRRR probability of thunder is very reserved, limiting even 10 percent chances on our doorstep until Tuesday afternoon. So, will keep thunder chances out until Tuesday.

By Tuesday, the upper low pressure system is in the Tennessee River valley. The low level jet axis over the area today will be more to our east on Tuesday, but 850 mb theta-e will be a little tomorrow afternoon/evening than today. Between 1000 to 2000 J/kg of MUCAPE will be around Tuesday afternoon and that coincides with the HRRR thunder output mentioned earlier. This is likely more scattered showers/storms and shear appears lacking keeping this sub-severe. A similar day for chances for showers/storms is expected on Wednesday with the upper low's energy now overhead to begin to shift eastward.
Similar instability readings exist and legitimate keeping keeping showers and storms in the forecast especially for the afternoon.

Ridging moves in for Wednesday night into Thursday as the upper low moves out, east of the area giving way to a trough hot on its heels.
Surface dew points reach the mid 60s and approach 70 degrees on the ECMWF and 850 mb temperatures approaches 18C by day's end. So, should maximum heating become realized, 90 degrees is not out of the question. 90 degree temperatures certainly have been done before, but it may be a little on the early side climatologically. At the very least, temperatures well into the 80s can be expected as long as debris clouds from Wed night/Thu AM rain don't eliminate the chances. That lingering ridging may be able to keep us from that. Better kinematics arrive later day and that'll help to increase shear that can be tapped into by storms that may form.
One interesting signal on the GFS is that shear drops off across the area around 00z which may be as a result of its modeled convection. Southern areas may be able to see 2000 J/kg of MUCAPE according to the ECMWF. One issue for convective initiation chances could be forcing, which appears to be fairly weak, especially if capping takes hold with these hot conditions. A cold front finally arrives right around 4 or 5z.
GFS-modeled helicity actually pushes into NW OH already by 00z, which is disconnected from other ingredients. Mid level lapse rates around also between 7 and 8 C/km with 900 J/kg of DCAPE lingering behind an initial batch of over 1000 J/kg during the afternoon. All this to say that all threats are on the table, but that there are questions with ingredients lining up to get those threats out of the storms.

Theta-e output shows the atmosphere is overturned on Friday after the cold front goes through, but models stall the front just to our south in southern Indiana. As a result, enough baroclinic instability is around to allow another instance of showers and storms there. Really on 500 to 1500 J/kg of MUCAPE exists across the area according to the GFS (lesser on the ECMWF) so the storm chance is lesser, but not negligible. Will carry slight to chance PoPs for later Friday into Friday night for this chance for rain/storms.

Again, it looks like another dry weekend is in store as the upper that affects us late week and traverses north of the area finally shifts eastward, away from the area.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
Issued at 814 PM EDT Mon May 12 2025

VFR conditions to start the period with light showers around and E-SE flow, however expect some deterioration to MVFR/possibly IFR as a low pressure system moves in overhead tonight. As of this writing, models are forecasting too low of ceilings based on surrounding observations and those upstream-so was not as pessimistic with the IFR conditions as previous forecast. Still, do expect some lowering given the system moving in tonight, with any shower activity fairly limited. Most of the guidance drops ceilings tonight to around 700 to 1500 ft at KFWA [slightly higher at KSBN more in the 1500-3000 ft range outside of a few brief periods later tonight/Tue AM]. We'll see a break in the shower activity in the late morning/early afternoon before we have chances for scattered showers and maybe even a few thunderstorms in the mid-late afternoon. Have handled T-storm chances with Prob30's for now given lower confidence on exact timing/location.



IWX WATCHES/WARNINGS/ADVISORIES
IN...None.
OH...None.
MI...None.
MARINE...None.